Closeup shots of prospective NASA Project Mercury astronaut Hal Crandall as he undertakes the Harvard step and tilt table test at Wright-Patterson Air Force Base, Ohio. Crandall steps 20 inches to a platform once every two seconds for five minutes. He also lies on steeply inclined table for 25 minutes to measure ability of the heart to compensate for body in an unusual position for an extended time. Doctors take blood pressure while Crandall is on tilt table.